Tulo

Sugar Cookie Frosting Recipe

A butter knife spreading glossy white icing over a star-shaped sugar cookie on a cooling rack, with a bowl of extra icing and a small dish of sprinkles beside it.
Photo by Aleyna Yetkin on Pexels

Powdered sugar and milk alone can taste chalky and dry out matte, but a spoonful of corn syrup keeps the icing glossy and slightly pliable as it sets, so cookies stack without the frosting shattering or looking dull.

Prep
10 min
Cook
0 min
Total
10 min
Servings
24

Ingredients

Servings24
  • 4 cups powdered sugar, sifted
  • 4 tablespoons milk
  • 2 tablespoons light corn syrup
  • 1 teaspoon vanilla extract
  • 1/4 teaspoon almond extract (optional)
  • 1/8 teaspoon fine salt
  • 0 as needed gel food coloring (optional)

Nutrition per serving

Calories
85
Protein
0g
Carbs
21g
Fat
0g

Based on the recipe as written, one serving. Recalculates if you swap an ingredient above. An estimate only, exact values depend on the specific ingredients used.

Need different units or a different yield? Try our Conversion Calculator →

Instructions

  1. 1In a medium bowl, whisk the sifted powdered sugar and salt together to break up any lumps.
  2. 2Add 3 tablespoons of the milk, the corn syrup, vanilla extract, and almond extract (if using). Whisk until completely smooth, no dry streaks of sugar left.
  3. 3Check the consistency: for spreading with a knife, it should hold a ribbon for about 5 seconds before disappearing back into the bowl. Add the remaining milk a teaspoon at a time to loosen it, or a tablespoon more powdered sugar to thicken it, until it reaches that point.
  4. 4If piping outlines or flooding cookies, divide the icing into separate bowls before thinning further; outline icing should be stiff enough to hold a peak, while flood icing should settle flat within about 10 seconds of spreading.
  5. 5Tint each portion with gel food coloring, stirring until the color is fully even, then transfer to piping bags or spread directly onto cooled cookies with an offset spatula or the back of a spoon.
  6. 6Let iced cookies sit uncovered at room temperature for 4 to 6 hours, or overnight, until the surface is dry to the touch before stacking or packaging.

Tips & variations

  • Use gel food coloring rather than liquid drops; liquid coloring adds extra moisture that can throw off the consistency you just dialed in.
  • For a firmer icing that dries harder and holds detail piping longer, replace 2 tablespoons of the milk with 2 tablespoons of pasteurized egg white powder mixed with water, or swap in a meringue powder-based royal icing instead.
  • A drop of butter extract along with or in place of the vanilla gives a flavor closer to bakery-style frosted sugar cookies.
  • If the icing develops small air bubbles after piping, pop them with a toothpick within the first minute or two, before the surface starts to set.

Storage & reheating

Store unused icing in an airtight container at room temperature for up to 2 weeks, or refrigerate for up to a month; stir well before using since it separates slightly on standing. Fully set, iced cookies keep in a single layer or between sheets of parchment at room temperature for about a week; avoid refrigerating iced cookies, since condensation when they come back to room temperature can make the icing sweat and turn sticky.

Tips from the Tulo kitchen

  • Sifting the powdered sugar before whisking in the liquid prevents small hard lumps that never fully dissolve and show up as bumps once the icing dries.
  • Working in batches and keeping bowls of icing covered with a damp paper towel between uses stops a dry skin from forming on top before you're ready to pipe it.

FAQ

Why does this icing set hard instead of staying like a soft glaze?

As the milk evaporates over several hours, the sugar recrystallizes into a firm shell. The corn syrup keeps that shell from becoming brittle or cracking when the cookies are handled.

Can I make this without corn syrup?

Yes, though the finish will look flatter and matte instead of glossy, and the dried icing is more likely to crack if the cookies flex. Light agave syrup works as a substitute in the same amount.

How is this different from royal icing?

Royal icing is made with egg whites or meringue powder, which lets it dry rock-hard and hold fine piped detail almost indefinitely. This milk-based version stays a bit softer to bite through and doesn't need pasteurized egg products.

Why is my icing too thin even after adding more powdered sugar?

Adding sugar to an already-thin batch often just makes it grainy rather than thick. Let it sit for 5 minutes first, since it firms up slightly as it rests, then adjust with small additions of sugar rather than trying to fix it all at once.

Can this icing be piped through a fine tip for detail work?

Yes, if it's thickened to hold a stiff peak rather than the looser spreading consistency. Thin it separately for flooding and keep the piping batch thicker so lines hold their shape.